Inflammation may help explain depression, diabetes link

NEW YORK (Reuters Health) - People with both depression and
diabetes have higher markers of inflammation in their blood than
those with diabetes alone, a new study suggests.

Researchers have known that people with diabetes have a
higher rate of depression than those without the blood sugar
disorder. And people with both conditions tend to do worse over
the long run than people with diabetes but no depression.

Inflammation is a sign of the body responding to disease,
trauma or other stressors. The new study suggests higher
inflammation levels may help explain the link between diabetes,
depression and worse overall health, researchers said. But it's
still not clear how, exactly.

"We asked, why is depression so bad for diabetes? The study
suggests that we have a possible biological explanation," Dr.
Khalida Ismail told Reuters Health.

"Inflammation may be driving a number of different long-term
conditions. That's quite a new way of thinking of the mind and
the body," she said.

Ismail worked on the study at the Institute of Psychiatry at
King's College London in the UK.

She and her colleagues examined 1,227 people with newly
diagnosed type 2 diabetes.

Those who reported symptoms of depression tended to be
younger and heavier. They also had higher rates of heart and
circulation problems and higher concentrations of established
markers of inflammation in their blood, according to results
published in Diabetes Care.

After the researchers took into account other potential
differences between study participants, such as their age, sex,
amount of body fat and use of certain medications, six of the 12
inflammatory markers they measured were still linked to
depression.

More than one in 20 Americans reported depression in
2005-2006, and about one in 12 has diabetes, a major cause of
heart disease and stroke, according to the Centers for Disease
Control and Prevention.

Death rates are up to twice as high among people with
depression and diabetes as those with diabetes alone, Ismail
said.

"The conventional wisdom is that this is a consequence of
the psychological burden of having diabetes," she said. "If
that's the case, if you treat the depression, the diabetes
control should improve."

But it does not, Ismail said. So she began to wonder if
inflammation, often seen in people with diabetes, could help
explain both conditions and the worse outcomes.

"It's a bit like an engine," Ismail said. "You're running a
bit higher. So there's this constant low-grade inflammation and
that's causing damage to your brain, your pancreas and to your
vascular system."

Dr. Anne Peters said she often sees patients with diabetes,
depression and elevated markers for inflammation. But there are
still many questions about how they are related.

"The development of depression could in part be triggered by
inflammation, but we don't know what comes first," she told
Reuters Health. "This paper can't prove causality. The interplay
is so complicated."

Peters directs the University of Southern California
Clinical Diabetes Program in Beverly Hills and was not involved
in the current study.

"To me, it's as much a part of diabetes care as looking at
blood sugars to screen for and treat depression," she said.

She believes the best way to begin to combat both depression
and diabetes is to eat well and exercise. Her own study found
that depression scores among people with diabetes dropped when
they were physically active.

"If you exercise, you feel better, your inflammatory markers
improve. It's all about lifestyle interplaying with your health.
We're just living lives we were not made to live. We sit still
too much at work. We're caged up in a way," she said.

Peters cited a 2012 study that found that people taking
antidepressants were at higher risk for diabetes than
non-antidepressant users, even after taking their weight into
account. The current study did not examine antidepressant use.

SOURCE: http://bit.ly/1l3jaAj Diabetes Care, online May 19,
2014.

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